In recent years, extruded products containing reinforcement have been widely employed as various construction materials, structural materials and the like due to the development of the composite extrusion technique. However, the above-mentioned extruded products contain reinforcement which is simple in shape such as straight wire rods, plate strips, shape steel or glass fibers, but the reinforcement does not sufficiently possess the characteristics of high rigidity and light weight. When employing extruded products as a prop or beam, the extruded products containing shaped steel as reinforcement have greater weight, so that rather than use them, special and expensive honeycomb beams must be employed where high-rigidity and light weight are particularly required.